The present invention relates generally to a fiber array, and more particularly to a fiber array comprising a support post that permits the fiber array to be fabricated with reduced thickness.
Use of multiple optical channels has become prevalent in applications ranging from data communications to optical imaging in response to a need for increased system bandwidth. At the same time, miniaturization still remains an important goal in these applications. High fiber packing density assists in effecting miniaturization and increasing the space-bandwidth product. In addition, integration of components is an important engineering design principle in many applications. Integration of components effectively decreases the number of parts, which decreases the number of degrees of freedom among components, thereby simplifying product assembly.
In many of these systems, multiple optical channels take the form of optical fibers which communicate with other devices or other fibers of the system. A fiber array provides a desirable way for handling multiple optical fibers while attempting to effect miniaturization, decrease the degrees of freedom among the fibers, and increase the packing density of the fibers.
Typically, a fiber includes an inner core and cladding enclosed within an outer jacket. For maximizing packing density, only the information carrying portions of the fiber need be accessible at the input and output portions of an array. Thus, only the core and surrounding cladding of a fiber need to be accessible at the input and output of the array. The jacket, which typically surrounds the cladding, provides structural support for the core and cladding but performs no optical function. For example, a fiber may have a jacket diameter of 250 microns and cladding diameter of 125 microns. Therefore, the removal of the jacket permits an increase in the linear packing density by a factor of 2.
In certain applications it becomes highly desirable to stack linear fiber arrays to create a two-dimensional array of optical fibers. In order to maximize packing efficiency in a two-dimensional array, high fiber packing density must be achieved in both directions of the two-dimensional array. One way to effect a higher packing density is to minimize the dimensions of the fiber array. To this end, it is desirable to provide a fiber array to precisely hold un-jacketed fiber segments and provide structural support to those segments. However, providing that support requires that the fiber array be sufficiently rigid itself, which in turn places limits on minimum acceptable dimensions of the entire array.
In accordance with the present invention, a fiber array is provided having a reduced dimension, such as height, made possible through the use of one or more support posts in an open cavity of the fiber array.
In general, a basechip is provided for use in the support of an array of optical fibers. The optical fibers may be of the type having a large-width section of a predetermined width and an adjoining small-width section of relatively smaller width. A grooved support section is provided on the basechip having a series of longitudinally extending grooves dimensioned to receive the small width sections of the fibers and to hold the small width sections between the basechip and a mating enclosing lidchip. An enlarged recessed area adjoins the grooved support section and is dimensioned to receive the large-width sections of the optical fibers to hold the large width sections between the basechip and the enclosing lidchip. A support post is disposed within the recessed area to provide support within the recessed area relative to the basechip and the lidchip. The support post provides passageway channels within the recessed area on opposite sides of the support post for holding the large-width sections of the optical fibers.
The lidchip may be combined with the basechip to provide a support structure for the array of optical fibers. The lidchip may include a recessed area that can be positioned in registry with the recessed area of the basechip to form a fiber holding cavity for holding the large-width sections of the optical fibers. In a second embodiment, the support post may include a first support post section positioned within the recessed area of the basechip and a second support post section positioned within the recessed area of the lidchip to form a unified support post within the cavity when the lidchip is closed on the basechip. The lidchip may include a mating surface for enclosing the grooves on the basechip. Alternatively, the lidchip may include a grooved section providing a series of grooves dimensioned to register with the grooves on the basechip to form fiber holding channels for supporting and holding the small-width sections of the optical fibers. In application, the large-width sections of the optical fibers may include jacketed segments of optical fibers and the small-width sections may include un-jacketed sections of the optical fibers. The un-jacketed sections of the optical fibers may be enclosed within a cladding having a smaller outside diameter than the jacketed segments of the optical fibers.
In an alternate embodiment, basechip support is provided for a fiber array having a front face and a rear face. A top mating surface is provided on the basechip having a plurality of grooves formed therein. The grooves extend along a longitudinal axis and have first and second open ends. The first open ends of the grooves are positioned proximate to the front face of the basechip. A first recessed area extends downward into the basechip from the mating surface in deeper distance than that of the grooves. The recessed area is formed by a base surface recessed below the mating surface. The recessed area includes a first transverse sidewall positioned at the second open ends of the longitudinal grooves. Second and third side walls extend longitudinally from the first transverse side wall to the rear face of the basechip. The base surface adjoins the lower edges of the first, second and third side walls. At least one support post extends upwardly from the base surface within the recessed area toward the mating surface. The support post has an upper support surface for engaging a mating enclosure structure for providing support within the recessed area.
In a more specific configuration, the fiber array of the present invention includes front and back face walls, the back face wall having a fiber receiving opening. A top wall extends from a top edge of the first face wall to a top edge of the back face wall to form an upper surface of the fiber array. Similarly, a bottom wall extends from a bottom edge of the front face wall to a bottom edge of the back face wall to form a lower surface of the fiber array. A fiber receiving cavity is disposed vertically between the upper and lower surfaces of the fiber array and communicates with the fiber receiving opening in the back face wall. The cavity comprises top and bottom interior walls disposed proximate to the respective top and bottom walls of the fiber array. A plurality of passageways are provided for receiving and holding optical fibers. The passageways have first passageway ends disposed at the front face wall to communicate with the exterior of the fiber array. The passageways have opposing second passageway ends disposed in communication with the fiber receiving cavity, and thus the passageways extend from the first end wall to the fiber receiving cavity. A support post is disposed within the fiber receiving cavity and extends from the bottom interior wall to the top interior wall. A plurality of optical fibers, having a central core surrounded by a cladding covered by a jacket, are disposed within the fiber array. The fibers have an unjacketed core segment from which the jacket has been removed from a first end of the optical fibers. The un-jacketed core segment of the optical fibers is disposed within the passageways with the first end of the optical fibers located proximate to the front face wall of the fiber array. The fibers also have a jacketed segment adjoining the un-jacketed core segment from which the jacket has not been removed. The jacketed segment of the optical fiber is contained within the fiber receiving cavity. The support structure for a fiber array may be created from a separate basechip and lidchip.
A basechip is formed to have a first mating surface in which a plurality of longitudinally extending grooves are formed. The grooves extend along a longitudinal axis and have first and second open ends. The first open ends of the grooves are located proximate to a front face of the basechip. A first recessed area extends into the basechip from the first mating surface. The first recessed area includes a first sidewall extending transverse to the longitudinal grooves. The first sidewall is positioned to adjoin the second open ends of the grooves. The first recessed area also includes second and third sidewalls which extend generally longitudinally away from the first sidewall. A base is provided for the recessed area that adjoins the first, second, and third sidewalls. The basechip includes at least one support post which extends upwardly from the base intermediate the second and third sidewalls and has an upper support surface located generally in the plane containing the first mating surface. A complementary lidchip is formed for combination with the basechip to create the fiber array support structure.
The lidchip comprises a second mating surface which is substantially in facing contact with the first mating surface of the basechip. A complementary recessed area extends into the lidchip and has a base wall that provides the bottom of the complementary recessed area. The complementary recessed area is positioned in registry with the first recessed area to form a fiber holding cavity. The lidchip may include at least one complementary support post which extends from the base wall of the lidchip. The complimentary support post has a mating support surface located proximate to a plane containing the second mating surface. The mating support surface is positionable in substantially facing contact with the upper support surface of the support post of the basechip to form a support post through the fiber holding cavity. Within the combined structure of the basechip and lidchip, a plurality of optical fibers are held. The fibers have an un-jacketed core segment and an adjoining jacketed segment. The un-jacketed core segments of the optical fibers are disposed within the grooves of the basechip, whereas the jacketed segments of the optical fibers are disposed within the fiber holding cavity formed by the conjoined recessed areas of the lidchip and the basechip. In addition, the lidchip may optionally include complementary grooves in the second mating surface located for registry with the grooves of the basechip to form elongated channels for receiving and holding the un-jacketed core segments.
The fiber array of the present invention, through use of the support post, permits the array to have a reduced height by enabling reduction in the thickness between the upper surface of the fiber array and the top interior wall. The support post likewise permits a decrease in the thickness between the lower surface of the fiber array and the bottom interior wall of the fiber array.